May 29, 2018 – A novel intervention acutely reduced intra-cardiac filling pressures and improved cardiac output and patient symptoms.
In a first-in-man proof-of-concept study, DCRI researchers recently tested a new therapeutic approach for the treatment of acute heart failure (HF). Promising results identified the splanchnic nerve as a potential therapeutic target for improvement in acute HF.
DCRI Fellow Marat Fudim, MD, presented the study May 26 at the European Society of Cardiology’s Heart Failure 2018 congress in Vienna, Austria. The DCRI’s Adrian Hernandez, MD, MHS; Schuyler Jones, MD; Cynthia Green, PhD; and Manesh Patel, MD, co-authored the study, which was published simultaneously in Circulation.
The study objective was to assess the effect of a temporary splanchnic nerve block (SNB) on hemodynamic, laboratory, and functional outcomes in patients admitted for acute HF. The trial was prospective, open-label, and included a single-arm intervention in five patients who were hospitalized at Duke University Medical Center between April and November 2017.
Each patient had an established history of HF with elevated intra-cardiac filling pressures on baseline right heart catheterization. The average age was 55 years, four of five patients were male, and ischemic cardiomyopathy was observed in three of the cases. Patients with coagulopathies and those on oral anticoagulants or P2Y inhibitors were excluded.
Five of the seven patients underwent the procedure, which involved a right heart catheterization in the supine position. A bilateral temporary percutaneous SNB with lidocaine was then injected into nerves close to the spine using fluoroscopic guidance in a prone position.
“We basically tried to numb as many nerves as possible going to the abdominal compartment,” said Fudim. “Once the patients were turned back over, we measured pulmonary artery mean and pulmonary capillary wedge pressures for 90 minutes. And what we found was that the pressures dropped immediately – below baseline. And there were no hemodynamic complications, including bleeding.”
Moreover, according to Fudim, patients reported an acute improvement in secondary outcomes during the procedure, including less shortness of breath and an increase in average 6-minute walk distance by 31 meters from immediately before to after the procedure, which however did not meet statistical significance.
The abdominal vascular compartment provides the main storage for intravascular blood volume, and decreased “storage space” could contribute to the complex pathophysiology of HF. Volume overload and inappropriate volume redistribution from the abdominal to the thoracic compartments may increase intra-cardiac pressures and bring on acute HF symptoms, Fudim said.
“Patients with HF essentially push fluid from their belly into the chest, which the heart can’t handle,” he said. “So the question was whether blocking the nerves would shift that fluid from the chest back to the belly – and it did. This is the first time we’ve had evidence of this nerve’s importance – the procedure was able to redistribute the fluid appropriately.”
The minimally invasive and regional nerve block indicated that the splanchnic vascular compartment may play a key role in both acute and chronic HF. These findings suggest that continued research into the use of SNB to treat HF could be of interest, according to Fudim.
“Though promising, however, we’re very cautious to propose this as a therapeutic intervention at this time,” he said. “The procedure can only be performed by an anesthesiologist, and the results are temporary. In addition, the lack of a control group is a major limitation to our study. More testing for safety and efficacy is needed before potential clinical application.”